The present invention relates to a method and a system for minimizing the use of mobile telephones in certain areas.
Today mobile telephones are becoming more and more frequent. The use of mobile telephones has in many regards facilitated the daily life for many people. However, in some places the use of mobile telephones is not appreciated and in some places even prohibited. Thus, mobile telephones are not liked in restaurants, libraries, churches etc.
Therefore, there is a need for a mobile telephone system, which minimizes or completely removes the possibility to use a mobile telephone in certain restricted areas.
In order to solve this problem a number of different solutions have been proposed. Thus, the international patent application WO 97/49255 discloses a method for eliminating the disturbance caused by a mobile station located in a certain area. The mobile station is provided with a control means, which mutes the mobile station upon receiving a particular message transmitted from a transmitting means provided in the certain area.
In the European patent application EP-0,880,296 a transmission restricting system is disclosed. The system comprises means for generating and radiating a magnetic field pattern, which includes a command signal, which commands a transmission interruption to a radio communication terminal.
However, the solutions provided according to WO 97/49255 and EP-0,880,296 both require additional hardware to be installed in existing mobile telephones. This is of course a drawback, since in order to work properly all existing mobile telephones would have to redesigned or exchanged.
In the UK patent application GB 2,317,304 another solution to the problem is disclosed. According to the system disclosed in GB 2,317,304 a base station in a mobile telecommunication network is provided with a message transmission function which is installed near the place where use of a mobile telephone is restricted. When a mobile unit enters the area managed by the base station having the message transmission function, a message is transmitted from the base station to the mobile unit instructing the mobile unit to turn off a power supply for the mobile unit.
However, even though not requiring additional hardware in the mobile telephones, the system as described in GB 2,317,304 does not provide an optimal solution. Thus, a base station is expensive and hence the system described in GB 2,317,304 will be expensive and also the location of the base stations must be chosen so that the area covered by the base station corresponds to the restricted area, which location probably will not be the optimal location for the radio system as a whole and a part of which is formed by the base station having the message function.
It is an object of the present invention to provide a method and a system, which reduces or eliminates the use of mobile telephones in restricted areas, and which at the same time does not require any change in the hardware of the mobile telephones or the existing mobile telephone network and which is inexpensive to implement and does not affect the planning of a radio system, such as the location of radio base stations.
This object and others are obtained by a system comprising a stand-alone device arranged to force a mobile station or telephone entering a restricted area to register in the system. The device issues a message to the mobile telephone instructing the user to turn off the telephone, when the mobile telephone enters the coverage area of the device.
Thus, a system is provided, which is arranged to transmit messages to mobile communication devices, without affecting the normal communication in the mobile communication networks. The system is implemented as a stand alone device, which can be located at any suitable location where mobile telephone communication is not desired, even in location where there is no coverage by mobile telecommunication networks.
Such a standalone system is preferably able to transfer a predefined message in text or voice format to the mobile communications device. This is obtained in that the system is designed to detect and force the mobile station to lock on to a control channel of the system. Thereafter the system transmits a predefined text or voice message to the mobile telephony device users within the coverage area of the stand-alone system.
An application area is to prevent mobile telephony device users to have the device switched on in radiosensitive areas such as hospitals and aeroplanes. The device could also suitably be located in libraries, churches and theatres where ring signals and conversation is of disturbing nature. Another possible application would be to deliver warnings about special conditions in certain areas. That could be useful in areas where an accident in a rural area not covered by the PLMNs to make people aware of an accident. The system can be mounted on an emergency vehicle. It can also be used for transmitting adverts locally in a shopping mall.
Since the stand-alone device is not required to be connected to a mobile telephone system it is easy to move around and in-expensive to manufacture.